A Hillsborough man pleaded guilty this week for selling at least 24 tons of misbranded synthetic drugs through his six California smoke shops and distributing other illegal hallucinogenic-containing products that were deemed unfit for human consumption, according to the Department of Justice.

Victor Anthony Nottoli, 51, forfeits more than $6.6 million in drug proceeds — $6.488 million in cash and $191,000 in other assets including a truck and an Airstream trailer — as part of his plea deal on charges of conspiracy to defraud the United States and one count of causing the tons of misbranded smokable synthetic cannabinoids to be introduced into interstate commerce.

Nottoli generated more than $20 million by distributing the products commonly known as K2 or spice in his chain of “The Stuffed Pipe” shops in Fresno, Visalia and Bakersfield and through nationwide retail outlets between April 1, 2011, and June 26, 2013, according to court documents. The products were first produced and distributed from a Millbrae warehouse before moving in January 2013 to a warehouse in Stockton.

The synthetic drugs, which were labeled “not for human consumption, included the hallucinogenic chemical compounds AM-2201 and XLR11 which are considered illegal Schedule I drugs.

They were referred to by Nottoli and his partners as herbal incense, spice, botanicals and potpourri and marketed under name like “Bizarro,” “Posh,” “Sonic Zero,” “Headhunter,” Neutronium” and “Orgazmo.”

Nottoli also admitted selling at least 24 tons of drugs without the legally required labels including manufacturer, contents, directions, warning against use by children and dosage warnings.

“The use of synthetic or designer drugs has increased dramatically among teenagers and young adults. Although synthetic cannabinoids are marked as ‘legal’ alternatives to marijuana they are not only illegal but can be extremely harmful,” said U.S. Attorney Benjamin B. Wagner in announcing Nottoli’s plea.

Twenty-six types of synthetic drugs, including the Am-2201 found in Nottoli’s products, were placed on the Schedule I list by the Synthetic Drug Abuse Prevention Act signed into law by President Barack Obama in 2012. XLR11 was added last May after the Centers for Disease Control and Prevention found it causes acute kidney injury.